Circuit breaker



A1153, 1943. H. EAXTER CIRCUIT BREAKER Filed Dec. 2, 1941 s Sheets-Sheet 1 Insu/af/bn INyENTOR Ham/d GBaxzer:

a, BY ;L/

ATTORN WITNESSES:

Aug 3, 1943; a. s. BAXTER cmciJIT BREAKER Filed Dec. 2, 1941 3 Sheets-Sheet 2 v. a m

INVENTOR Harold GBGXZ'GZ'. BY iL/ q ATTORN WITNESSES:

ns-- 19430 H. G. BAXLI'ER 2,325,650

CIRCUIT BREAKER Filed De'c? 2, 1941 s Sheets-Sheet 3 Inau/a /05 INVENTOR Harold 6154x167.

Patented Aug. 3, 1943 CIRCUIT BREAKER Harold G. Baxter, Wllkinsburg, Pa, asslgnor to Westinghouse Electric & Manufacturing Com- Dally, East Pittsburgh,

Pennsylvania Pa., a corporation of Application December 2, 1941, Serial No. 421,301

19 Claims.

ing operable independently of the other to interrupt the circuit.

Another object of the invention is the provision of an improved circuit breaker having a pair of cooperating contact means and a mechanism which is manually operable to move one of the contact means to open and to close the circuit, and having current responsive trip means operable to cause movement of the other contact means to an open position to automatically open the circuit in response to predetermined overload conditions.

Another object of the invention is to provide an improved circuit breaker having a pair of cooperating contacts and a mechanism which is manually operable to cause movement of one of the contacts to open and to closed position with a snap action, and having current responsive trip means operable to cause movement of the other contact to an open position to automatically open the circuit in response to predetermined overload conditions.

Another object of the invention is the provision of an improved circuit'breaker having a pair of cooperating contact means and a mechanism which is manually operable to move one of said contact means to open and to close the circuit, and having current responsive trip means operable to cause movement of the other contact means to an open position to automatically open the circuit in response to predetermined overload conditions, said other contact means being manually moved to a closed position by operation of the mechanism to open position.

Anotherobject of the invention is the provision of a circuit breaker having an operating mechanism operable by' a manual operating handle to open the contact means and which will reclose the contact means upon release of the handle,-

and having current responsive trip means operable to. cause automatic opening of the con tact meansirrespective of the position of the mechanism or handle.

Another object of the invention is the provision l8 19, an arc extinguisher of a circuit breaker having an operating mechanism operable by a manual handle to close the contact means and which will open the contact means upon release of the handle, and having a current responsive trip means operable to cause automatic opening of the contact means irrespective of the position of the operating handle and independently thereof.

Another object of the invention is the provision of an improved circuit breaker which is simple. safe and reliable in operation and which is inexpensive to manufacture.

The novel features that are considered characteristic of the invention are set forth in P ticular in the appended claims. The invention itself, however, both as to structure and operation, together with additional objects and advantages thereof, will be best understood from the following description of a single embodiment thereof when read in conjunction with the accompanying drawings in which:

Fig. 1 is a vertical sectional view through a circuit breaker embodying the'principles of the invention, taken substantially on line 1-1 of Fig- 5 and showing the breaker in the manually opened postion.

Fig. 2 is a view similar to Fig. 1 but showing the breaker in the closed position.

Fig. 3 is a view similar to Fig. 1 but showing the breaker in the automatically tripped open position.

Fig. 4 is a vertical sectional view through the breaker similar to Fig. 1 but showing the overcenter spring adjusted to bias the manual operating lever and the manually operable contact arm to the'open position.

Fig. 5 is a vertical transverse sectional view through the breaker taken substantially on .line V--V of Fig. 1, and

Fig. 6 is a vertical sectional view similar to Fig. 1 but showing the overcenter spring adjusted to bias the manual operating lever and the manually operable contact arm to closed position. InFig. 6 the breaker is normally closed and when opened manually will automatically reclose when the manual operating lever is released.

Referring to the drawings, particularly to Fig. 2, the circuit breaker is of the single pole type and comprises, generally, a base H of molded insulating material, a removable cover I! also of molded insulating material, a U-shaped manual operating lever IS, a switcharm l1 operable by the operating lever IS, a pivoted contact lever 2|, a trip device 28 and terminals 25 and 21 for connecting the breaker in an electrical circuit.

The U-shaped operating lever l comprises a pair of parallel levers pivotally supported at their inner ends on a pivot pin 29 mounted in the side walls 3| of the base II and Joined at their outer ends by a yoke 33 (Fig. 5). A manual operating handle 35 of insulating material is suitably secured to the yoke ,33 of the lever l5 and projects through a slot 31 in the cover |3.

The switch arm I1 comprises a pair of parallel arms of conducting material pivotally supported on pivot studs 39 projecting inwardly from each of the side walls 3|. At their free ends the switch arms are provided with inwardly formed ears 4| to which is secured, by rivets or other suitable fastening means, a contact member 43.

An overcenter spring 45 has one end hooked through an opening in a projection 41 on the yoke pivotally mounted at a point near its apex on a pivot comprising a bolt 55 mounted in bosses.5'| moulded integral with the base Suitable openings are countersunk from the outside of the base to receive the head of the bolt 55 and a nut 59 (Fig. 5) which secures the bolt in place.

One arm 5| of the contact lever l9 carries a contact 63 which in the closed position of the breaker cooperates with the contact 43, to complete the electrical circuit through the breaker.

The other arm 65 of the contact lever H! has secured thereto a bar 61 of insulating material,

and the bar 61 carries a latch member 69 which cooperates with the trip device 23 to releasably restrain the contact lever IS in the closed circuit position shown in Fig. 2. A spring coiled about the pivot 55 has one end bearing against the base and the other end bearing against the arm 6| of the-contact lever Hi to bias the latter in a clockwise or contact opening direction.

The trip device 23 comprises a bimetal element 13 rigidly secured to the formed over inner end of the terminal 25, and this bimetal element at a point near its'free end carries alatch 15 which cooperates with the latch member 69 to releasably. restrain the contact lever IS in closedposition. The free end of the bimetal element is electrically connected to the arm 55- of the contact lever l9 by means of a flexible conductor 11 the terminals of which are secured respectively to the bimetal element and the arm 55 by screws 19 and 8|. The switch arm I! is electrically connected to the inner end of the terminal 21 by means of a flexible conductor 83. The conductor 83 is secured-to the terminal 21 by a screw 85 V and is crimped to the switch arm H at 81 thus completing the electrical circuit through the breaker which circuit may be traced from the terminal 25 through the bimetal element 13, the flexible conductor contact lever IS, the contacts 63 and 43, switch arm I}, and the flexible conductor 83. to the terminal 21.

The are extinguisher 2| may be of any suitable type, preferably of the slotted magnetic plate type in which the arc drawn by rupture of the current is drawn into the extinguisher and broken cooled and extinguished.

The circuit breaker is manually operated to open the contacts by rotating the lever |5 in a counter-clockwise direction from its Fig. 2 posiup into a plurality of short arcs and quickly tion to the Figure 1 position. As the lever I5 is rotated the line of action of the overcenter spring 45 passes to the left of the center line 39-49 and exerts a force which biases the switch arm II in |5 in its "oil" position against the limit stud 53.

The parts will remain in this-position until the manual lever I5 is manually rotated clockwise toward its on position. During the clockwise movement of the lever l5 the line of action of the spring 45 passe to the right of the line 39-19 causing the switch arm I! to rotate to its closed position with a snap action. In the closed position of the lever 15 and switch arm I! the spring 45 biases these parts to their closed positions;

The breaker is tripped open automatically by the trip device 23 in response to an overload current of greater magnitude than that for which the breaker is rated. The bimetal element I3, which is connected in series relation in the circuit controlled by the breaker, is heated by excessive current flowing therethrough, and when heated a predetermined amount its free end flexes toward the left-(Fig. 3) causing the latch 15 to free the contact lever l9, whereupon the spring I acts to rotate the contact lever l9 clock-' wiseabout its pivot 55 thereby moving the contact 53 to open position away fr'omthe contact 43. The clockwise movement of the contact lever I9 is limited by the insulatingbar 51 striking an angular member 89 rigidly secured to a cross bar 9| connecting the levers forming the manual operating lever I 5. When the contact lever I9 is rotated clockwise the spring 45 rotates the switch arm slightly counterclockwise until it is arrestedby striking the limit stop 5|.

After the breaker has been tripped open automatically the contact lever l9 must be reset before the contacts can be closed. Resetting is ac complished by manually operating the operating lever l5 counterclockwise to the oil position.

. Movement of the lever l5 counterclockwise to the 011' position rotates the contact lever .|9 also counterclockwise by means of the angular member 89 to relatch the latch member 83 with the latch 15 on the bimetal element. Movement of the lever |5 to the o position (Fig. 1 also moves the spring 45 overcente'r and causes the switch arm I! to move to its open position shown in Fig. 1.- The contacts can then be closed by movement or the manual operating lever IE to its on position in the previously described man- It is frequently desirable, in 7 control circuits. to provide switches which are normally open but which may be momentarily closed manually y .an operating handle and which,-upon release or the handle, will automatically'reopen. Also it is desirable to provide in such circuits, switches which are normally closed. but which may be opened momentarily by a mantest circuits and V 2,325,650 ually operable handle and which upon release oi! the handle will automatically reclose.

One of the important features of the instant invention is to provide a circuit breaker which functions as a conventional circuit breaker which is operable manually to open and close the circuit and operable thermally in response to overload currents to automatically open the circuit and which, by a simple adjustment, can be made to function in the manner set forth in the preceding paragraph. This is accomplished by providing a plurality of points of anchorage for the overcen'ter spring 45 to the switch arm I'I. One of these points is so located that the operating lever'l5 is always biased to its off position, and the other point is located so that When'the spring 45 is attached thereto the lever I is biased to its on position.

Referring to Fig. 4, the overcenter spring 45 may be attached to the contact arm I! at any one of three points designated as the pin 49, a

in 49a, and a pin 4%. In Fig. 4 the spring 45 is shown attached to the pin 49a and normally biases the switch arm Il clockwise to its open position, and biases the operating lever I5 counter-clockwise to its "011 position. Movement of the operating lever to its -on position moves the line of action of the spring 45 to the right of the line 39-49a causing the contact arm 'to' move counterclockwise to its closed position with a snap action. However, with the lever I5 in its on position and the switch arm H in the closed position, the spring 45, tensioned between 41 and 49a doe'snot move overcenter to the right of the line 2941and, therefore, continuesto bias the operating lever I5 in a counterclockwise direction. Consequently, upon release of the handle 35, the spring 45 moves the lever I5 to its oil position. During'this movement, the

' line of action of the spring passes to the left of the line 39-4911 which results in moving the switch arm -I 'I to its open position.

. Referring now to Fig. 6 it may be seen that the spring 45 has its inner end hooked over the pin 49b. The parts are shown in Fig. 6 in their open position and it can be observed that, in the fully open position, the line of action of the spring 45 remains to the-right of the line 294'I and thus biases the operating lever I5 to its on position. When the handle 35 is released and the r spring 45moves the lever I5 clockwise, the line of action of the spring 45 passes to the right of the line 39-49b whereupon the switch arm I1 is moved to close the contacts with a snap action.

According tothe adjustment of the spring 45 as shown in Fig. 6, the operating lever I5 is normally biased to its on position and the switch arm I! is normally biased to its closed position, and after being opened manually will automatically return .to closed position when the handle 35 is released.

From the foregoing description it can be seen that the invention provides a circuit breaker which is both manually and automatically operable to interrupt a. circuit, and wherein two pivotally mounted contact members are movable each independently of the other, one being operable to interrupt the circuit in response to overload currents, and the other being manually operable to interrupt or close the circuit. It may be further observed that a simple adjustment has been provided whereby the breaker can be arranged to automatically close after having been" opened manually,'or whereby the breaker will automatically openv after having been closed man ually and the operating handle is released. In

irrespective of'theposition of the manualoperating handle.

Having described the invention in accordance with the patent statutes, it is to be'understood that various changes and modifications may be made in the structural details disclosed without departing from some of the essential features of the invention. It is, therefore, desired that the language of the appended claims be given as reasonably broad interpretation as the prior art permits.

I claim as my invention:

1. A circuit breaker comprising a switch member, operating mechanism for said switch member comprising an operating member movable to an open position and to a closed position, and

spring means operatively connecting the switch member and the operating member to cause movement of said switch member to an open position and to a closed position, said switch member being mounted for movement independently of said operating member, a contact member cooperating with the switch member and biased open, and current responsive means for releasably restraining said contact member in cooperative relation with the switch member, said current responsive means being operable in responsive to overload current to release said contact member.

2. A circuit breaker comprising a switch member, operating mechanism for said switch member comprising a manually operable member and resilient means connecting said manually operable member to the switch member for moving said switch memberto open and closed positions, with a snap action. a contact member cooperating with the switch member to complete an electrical circuit, means biasing said contact member in opening direction, and electroresponsive means for releasably restraining the contact member in closed position, said electroresponsive means being operable in response to predetermined conditions to release the contact member.

3. A circuit breaker comprising a switch member, operating mechanism comprising a member movable to open and to closed positions and an overcenter spring connecting said operating mechanism to said switch member for moving said switch member to open and closed positions, a pivoted contact member cooperating with said switch member, means biasing the contact member for movement in an opening direction away from said switch member, and a bimetal element for releasably restraining said contact member in a closed position, said bimetal element being operable when heated a predetermined amount to release the contact member.

4. A circuit breaker comprising a movable switch member, a manual member movable to an open position and to a closed position, an overcenter spring connecting said manual member to said switch member and operable uponmovement of the manual member to move the switch member to open and closed positions, a releasable contact member biased-open, and current responsive means for releasably restraining said contact member in engagement with the switch member when the manual member is in closed position, said current responsive means being operable in response to overload currents to release the contact member.

5. A circuit breaker comprising a pivoted switch member biased to closed position, a pivoted contact member biased to open position, an

operating member biased to a closed position and operable to an open position to'cause move-- ment of the switch member to open position,

said switch. member being mounted for movement independently of said operating member, and a trip device operable in response to predetermined circuit conditions to cause automatic movement of the contact member to open position. I I

6.,A circuit breaker. comprising a pivoted switch arm, operating mechanism for said switch arm comprising an operating member and an overcenter spring connecting said operating member to the switch arm, said operating member being operable to move the switch arm to open and closed positions, a pivoted contact member biased to open position, and current responsive means for releasably restraining said contact member in closed position, said current responsive means being operable in response to overload currents torelease the contact member.

"7. A circuit breaker comprising a switch member, an operating member movable relative to said switch member for moving said switch member to open and to closed position, a pivoted contact member movable relative to said switch member to openand closed position, means biasing the switch member to closed position at all times, electroresponsive means for releasably restraining the contact member in closed position.

and operable in response to. predetermined circuit conditions to release said contact member, .and spring means to move the contact member to open position.

8. A circuit breaker comprising a switch member biased to a closed position and movableto an open position, an operating member biased to a closed position and movable to an open position to cause movement '0! said switch member to open position, a releasable contactmember movable to an open position relative to the switch member, a thermal element operable when heated.

a predetermined amount to release said contact member, and spring means for moving the contact member to open position.

contact member, and a thermal element for releasably restraining said second contact member in closed position and operable when heated a predetermined amount to release said second contact memben.

11. A circuit breaker comprising a pivoted switch member movable to an open position and to a closed position, an operating member for said switch member, said operating member being ber movable to an open position and to a closed position, operating mechanism for said switch member comprising an operating member and a spring intermediate said operating member and said switch member, said spring being adjustable to cause automatic movement of the switch member to open position or to closed position according to the adjustment of said spring, a contact member biased to an open position and cooperating with the switch member in closed position, and a thermal element operable when heated a predetermined amount to cause movement 0 the contact member to'open position.

13. A circuit breaker" comprising a switch member movable to an open position and to a closed position, operating mechanism for said switch member comprising an operating member movable to open and closed positions and a spring intermediate the switch'memberand the oper- 9. A circuit breaker comprising a pivotedswitch member, an operating member for moving said switch member. to open position, biasing means connecting the switch member and said operating member biasing bothot said members to'closed position, said biasing means acting to move both of said members to closed position from an open position, a pivoted contact member, current responsive means for releasably restraining the contact member in cooperative relation with the switch member in the closed position, said current response means being operable in response to overload currents to release the contact member, and spring means to move the contact member to openposition.

10. A circuit breaker comprising a contact member having a normally closed position, an

ating member and operable by said operatingmember to move the switch member to open position, said spring acting to move. the switch member and the operating member to the closed position upon release of the operating member, a contact member having a closed position in which it is engageableby the .switch member in the closed position of said switch member, said 'contact member being biased to open position, and current responsive means operable in response to predetermined circuit conditions to cause movement of the contact member to open position.

14. A circuit breaker comprising a pair of pivoted contact members movable in opposite directions .to open and close the circuit, means operating member for manually moving said contact member to open position, means biasing the contact member and said operating member to closed position, said biasing means being effective upon release oi the operating member to' move both of said members to their closed peeltions, a second contact member ensageable by said first mentioned contact member in the closed position thereof, said second'contact member boing biased to openposition away. irom said ilrst biasing one of said contact members in opening direction, operatingmean including an overcenter spring biasing the other contact member closed and operable to .cause opening movement of said other contact member with a snap action,

and trip means operable in response to overload currents to cause opening movement of said one contact member. Y

.15. A circuit breaker comprising a pair of contact members movable in opposite directions to' close and open the circuit, means biasing one of said contact members in opening'direction,

operating means including a spring. biasing the other contact member open and operable to cause closing movement or said other contact member with a snap action, and electroresponsive means operable in response to overload currents to cause opening movement of said one contact member without displacing the operating means.

16. A circuit breaker comprising a pair of contact members movable in opposite directions to cause opening and closing of the circuit, operating means including an overcenter spring operable to cause movement of one of said contact members to open and to closethe circuit with a snap action,

means biasing the other contact member in opening direction, and current responsive means operable in response to predetermined circuit conditions to cause movement of said other contact member to open the circuit.

17. A circuit breaker comprising a switch member, operating means for said switch member comprising an operating handle movable to an open position and to a closed position, and an overcenter spring operable to move the switch justing said connection to cause automatic movemember to an open position and to a closed position, means for adjustably connecting said spring to one point of the switch member to cause automatic movement of the switch member to the open position when the handle is released in the closed position and to another point of said switch member to cause automatic movement of the switch member to closed position when the handle is released in the open position, a contact member cooperating with the switch member in the closed position and operable to an open position, a nd current responsive means operable in response to overload currents to cause operation of said contact member to open position.

18. A circuit breaker comprising a switch member, operating means for said switch member comprising an operating handle movable to an open ment of the switch member to the closed position when the handle is released in open position, a contact member cooperating with the switch member in closed position and operable toan open position, and a bimetal element operable when heated a predetermined amount to cause operation of the contact member to the open position.

19. A circuit breaker comprising a switch member, operating means comprising an operating member movable to an open and to a closed position, and spring means operatively connecting the switch member and the operatingmember to cause movement of said switch member to an open position and to a closed position, a contact member cooperating with said switch member in a closed position and biased open, and a thermal element for releasably restraining said contact member in closed position, said thermal element being operable when heated a predetermined amount to release the contact member, said operating member remaining in closed position following release of said contact member, and said operating member being operable toreset said contact member when said operating member is manually moved to open position.

HAROLD G. BAXTER. 

